Bioceramics 18

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Authors: S. Bertazzo, Celso A. Bertran
Abstract: In this work, Scanning Electron Microscopy (SEM) has been used to determine the size and morphology of bone mineral crystals obtained from hydrazine-deproteinated parietal bone and femur of Wistar rats aged 15 days, 1 month and 1 year. Apart from the Scanning Electron Microscopy study, crystal size was also determined by X-ray diffractometry, using the Debye- Scherrer equation. Analyzing the results obtained and those reported in the literature for isolated crystals, it is possible to evaluate the influence of age and type of bone on the nanostructure of bone mineral and also propose the existence of a fundamental morphological unit that repeats itself in bone mineral formation.
Authors: S. Bertazzo, Celso A. Bertran
Abstract: In this work, some modifications that occur in crystallites that compose the mineral phase of bone throughout the lives of animals were studied by X-ray diffractometry. The Debye-Scherrer equation was applied to the diffractograms, allowing the determination of the mean crystallite size and the changes in the mean crystallite size with relation to the diffraction planes 002 and 310. Likewise, the intensity of peaks in the diffractograms corresponding to the same diffraction planes was correlated with the number of crystallographic planes or of unit cells present in the crystallites.
Authors: S. Bertazzo, Celso A. Bertran, J.A. Camilli
Abstract: Some microscopy studies on the mineral phase of bone have been carried out either utilizing Optical or Scanning Electron Microscopy (SEM), generally around 1000x magnification, to observe the interaction between cells and bone mineral. Other studies have been utilizing Transmission Electron Microscopy (TEM), generally around 1000000x magnification, to observe the fundamental particles that form bone mineral. The literature lacks works that utilize Scanning Electron Microscopy around 10000x magnification, particularly suitable for the study of structures composed by the aggregation of fundamental particles. The objective of this work was to study the morphologic differences between the mineral phase of femur and parietal bone of Wistar rats. Observation of the micrographs showed that the microscopic morphology of the mineral phase of femur was very similar to that of the parietal bone. It was also possible to notice that the morphology of the mineral phases varied with age, yet this variation was practically the same for the material obtained from the two types of bones.
Authors: Kanthi Lewis, U. Boonyang, L. Evans, S. Siripaisarnpipat, Besim Ben-Nissan
Abstract: This study aims to characterize the structure and properties of crocodile bone to assess the potential for use in biomedical applications. Crocodile bone samples obtained from Thailand (Crocodylus siamensis) and Australia (Crocodylus porosus), being the tail and the tibia respectively, were treated to remove organic material and the inner spongy (trabecular) material. The dense cortical bone was used for comparative instrumental analyses. Specific comparisons were made against bovine cortical bone and pure synthetic hydroxyapatite. The material was then analyzed using simultaneous differential thermal analysis/thermogravimetric analysis (DTA/TGA), Fourier- Transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). Imaging of full bone samples was also conducted using an environmental scanning electron microscopy (ESEM). The SEM provided valuable information through the imaging of samples, showing a markedincrease in bone porosity for crocodile material when compared to bovine samples. The crystallinity and/or crystallite size of carbonated hydroxyapatite has been found to be lower than synthetic apatite, with the tibia being the least crystalline of the bone types studied. The crystallinity index (CI) is used as a measure of crystallite size and internal strain. The strain is affected by substitutions in the structure and these results provide a starting point for comparison of the resulting mechanical properties. There is a need for any biomaterial chosen for bone replacement to allow adequate osteointegration. Thus the study this far shows that crocodile bone is a very promising source of carbonated apatite for biomedical applications.
Authors: Taketoshi Suwa, Toshiro Sakae, Hiroshi Nakada, Racquel Z. LeGeros, Kihei Kobayashi
Abstract: Our studies previously demonstrated that new bone formed around implants can be classified into 3 or 4 types based on tissue structure and composition. Results of the present study, using polarized light microscopy, and microscopic Fourier transform infrared spectroscopic imaging (micro-FT-IR) and micro-XRD to examine different areas in the peri-implant new bone, suggest differences in crystallinity (crystal size) between pre-existing bone and peri-implant new bone.
Authors: It Meng Low, N. Duraman, Ian J. Davies
Abstract: Structure-property relationships in baby and adult teeth have been characterised using grazing-incidence synchrotron radiation diffraction and Vickers indentation. Similarities and differences between both types of teeth have been highlighted and discussed. Depth profiling results indicated the existence of contrasting but distinct gradual changes in crystal disorder, phase abundance, crystallite size and hardness within the baby and adult canine enamel, thus confirming the graded nature of human teeth. When compared to the adult tooth, the baby enamel is softer, more prone to fracture, but has larger hydroxyapatite grains.
Authors: Faik N. Oktar, H. Sayrak, S. Ozsoy, Nurettin Heybeli
Abstract: Different types of bone-graft substitutes have been developed and are in the market worldwide to eliminate the drawbacks of autogenous grafting. They vary in composition, strength, osteoinductive and osteoconductive properties, mechanism and rates by which they are resorbed and remodelled. Tooth derived hydroxyapatite (THA) is a novel biomaterial. This study was performed to determine the histological properties of THA on animals. A commercial coralline HA (CHA, Proosteon 200, Interpore Cross, USA) was used as control material. 20 sheeps were used and divided into 2 groups. Human THA (Group A) and CHA (Group B) materials were implanted to the tibiae of 10 sheeps for each group. The histological examinations of surrounding bone response were done 12 weeks after implantation. There was no significant difference histologically between group A and B. All materials were found to be surrounded by new bone tissue. THA was found to be as efficient as the standard CHA on histological basis. In addition, economical production of THA should be taken into consideration. Therefore, THA may be a viable alternative on bone grafting provided that clinical trials will be completed.
Authors: Hiroshi Nakada, Toshiro Sakae, Taketoshi Suwa, Racquel Z. LeGeros, Atsuko Gunji, Takao Kato, Kihei Kobayashi
Abstract: The purpose of this study is to determine the potential of the LEBRA-PXR imaging in investigating the details of newly formed bone around the dental implants. Transmission image observation of the undecalcified specimen at the wavelength of 1.771 Å showed clearly the formation of immaturely calcified new bone around the dental implants which could not be observed in the usual CMR nor conventional X-ray imaging apparatus.
Authors: H.J. Kang, M.J. Cho, J.H. Lim, D.K. Kwon, J.M. Lee, Hong In Shin
Abstract: Osteogenic repair is highly dependant upon the substrate carrier or matrix. As a part of the effort to develop a suitable scaffold optimizing bone regeneration, we evaluated the efficiency of bovine bone ash particles, prepared by ashing at 600 °C for 8 hrs and pulverizing to 150-250 µm size particles, as a scaffold for bone tissue regeneration. The non-cytotoxic bovine bone ash particles, evaluated by Agar over lay test, showed no disturbance in cellular proliferation and osteogenic differentiation in an in vitro cell culture system. Furthermore, the implanted bone ash particles in artificial bone defects on rat mandible revealed favorable biocompatibility and regeneration of bone and dentin associated with bone ash particles. The new bone and reparative dentin were well integrated with bone ash particles. These findings suggest that allogenic bone ash particles composed mainly of hydroxyapatite are applicable for repair of tooth related bone defects as well as pulp damaged tooth repair.
Authors: Sang Hoon Rhee, Ho Nam Park, Yang Jo Seol, Chong Pyong Chung, Sang Hyuk Han
Abstract: Effect of heat-treatment temperature on the osteoconductivity of the apatite derived from bovine trabecular bone was investigated. Three different heat-treatment temperatures (600, 800 and 1000 oC) were adopted in the experiment and their effects on the physical properties of apatite granules, which could affect on the osteoconductivity, were evaluated. The content of carbonate ions in the apatite structure was assessed by FT-IR and its crystallinity was evaluated by X-ray diffractometry. The microstructure was assessed by field emission electron microscopy. Apatite granules heat-treated at 600 oC and 1000 oC were implanted into the calvaria of New Zealand White rabbit for 4 weeks, respectively, and the undecalcified ground histologic specimens stained with multiple staining method was observed. As increasing the heat-treatment temperature, the crystal size and crystallinity of the apatite increased while the content of carbonate ions decreased. The apatite granules heat-treated at 600 oC showed much better osteoconductivity comparing to that heat-treated at 1000 oC. The results were explained in terms of the physical properties of apatite which could affect to the osteoconductivity.

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